In the prior art, when a packet is forwarded, layer two forwarding is guided according to exact matching of a media access control (Media Access Control; hereinafter referred to as MAC) address. When the packet is forwarded in Ethernet (Ethernet), the packet is forwarded to all interfaces in an unknown unicast flooding (Flooding) way if a matching MAC entry does not exist, thereby achieving a final effect for sending the packet to a destination.
The basic idea for an Ethernet virtual private network (Ethernet Virtual Private Network; hereinafter referred to as EVPN) is to learn the MAC address on a control plane by expanding a border gateway protocol (Border Gateway Protocol; hereinafter referred to as BGP) protocol, thereby realizing a function of layer two VPN (Layer two VPN; hereinafter referred to as L2VPN). Learning the MAC address on the control plane naturally solves the problems caused by performing MAC address learning on a data plane, such as difficulty to realize multi-homing of customer edge (Customer Edge; hereinafter referred to as CE) device, unknown unicast Flooding and address resolution protocol (Address Resolution Protocol; hereinafter referred to as ARP) broadcasting storm. However, with the development of cloud computing, the scale of a data center is expanding continuously, but the way for the EVPN to learn the MAC address on the control plane needs each provider edge (Provider Edge; hereinafter referred to as PE) device to store MAC address tables of all connected VPN sites, which needs very high capacity and performance of the PE device.
However, if a capacity limit is taken into account, and an overall MAC address table is not stored on a network device (for example, a PE device), when the packet is forwarded, the packet may be flooded on all interfaces if a MAC entry matching a destination MAC address of the packet does not exist in the MAC address table, but unnecessary network traffic may therefore be increased.